1. Field of the Invention
The present invention relates to a wiring unit having a first insulating layer provided with a power feeding electrode and a wire electrically connected to the power feeding electrode, on one surface thereof, and particularly to a wiring unit which is capable of connecting electrically the power feeding electrode and an object such as another electrode by a liquid electroconductive material, moreover, the present invention relates to a method for producing such wiring unit, a liquid jetting apparatus which is formed by using the wiring unit, and a method for producing the liquid jetting apparatus in which such wiring unit is used.
2. Description of the Related Art
An ink-jet printer, which has a channel unit provided with a liquid channel and which jets an ink from a jetting port formed at a downstream of the liquid channel onto a recording medium, has hitherto been known as an example of a liquid jetting apparatus. More elaborately, a pressure chamber having a predetermined volume is formed in the liquid channel, to have an opening partially, and a piezoelectric layer is provided such that the opening of the pressure chamber is covered. The piezoelectric layer is deformed by applying a voltage, and is sandwiched between a common electrode which is kept at a predetermined electric potential and a drive electrode to which a predetermined electric potential different from the electric potential of the common electrode is imparted by applying a voltage. Furthermore, in a connecting structure of a flexible circuit board disclosed in U.S. Pat. Nos. 7,055,936 and 7,370,943 (correspond to Japanese Patent Application Laid-open No. 2004-114609), a power feeding electrode for imparting a predetermined electric potential to a drive electrode is arranged in the vicinity of the drive electrode, and the drive electrode and the power feeding electrode are connected electrically by solder.
When an electric power is supplied to the power feeding electrode from an external power source, a voltage is applied to the drive electrode which is connected to the power feeding electrode, and there is a potential difference developed between drive electrode and the common electrode which is kept at the predetermined voltage. As a result, the piezoelectric layer is deformed, and a volume of the pressure chamber is also changed. Due to the change in the volume of the pressure chamber, a liquid inside the pressure chamber is pressurized and jetted to an outside from the jetting port via the liquid channel.
In general, solder has a poor flexibility when dried. Therefore, in a liquid jetting apparatus such as the one mentioned above, if an electrical contact between the drive electrode and solder is provided in an area corresponding to the pressure chamber when viewed from a direction of the thickness of the piezoelectric layer, when the voltage is applied, a deformation of a portion of the piezoelectric layer corresponding to the pressure chamber is hindered, and it is difficult to pressurize sufficiently the liquid inside the pressure chamber. Moreover, in order to secure the electrical contact between the drive electrode and the solder without hindering the deformation of the piezoelectric layer, it is necessary to extend a wire from the drive electrode up to an outside of the area corresponding to the pressure chamber, and to connect the wire and the solder. In other words, since it is necessary to extend a wire for electrical connection for each pressure chamber, in a case of an ink-jet printer which includes a plurality of pressure chambers, it becomes difficult to have a high integration of the pressure chambers. As a result, it becomes difficult to realize further compactness of the channel unit and further improvement in a resolution of a printed matter such as a photograph.